Non-magnetic 316L stainless steel and production method thereof

Abstract

The invention discloses non-magnetic 316L stainless steel and a production method of the non-magnetic 316L stainless steel. The non-magnetic 316L stainless steel is prepared from, by weight, 0.01-0.03of C, 1.0 or less of Si, 2.0 or less of Mn, 0.045 or less of P, 0.002 or less of S, 16.5-17.50 of Cr, 13.5-14.0 of Ni, 2.5-2.7 of Mo, 0.11 or less of N, 0.001-0.003 of B and the balance Fe and otherinevitable impurity elements, Md30 is -170 DEG C--200 DEG C, and delta ferrite is smaller than 0.5%; and steel billet smelting, plate billet heating, plate billet rolling, black coil annealing and pickling, modulation calendering, cleaning and oil removal processes are carried out. The non-magnetic 316L stainless steel has the advantages that the requirements for no magnesium, machining performance and corrosion resistance are all met, harmful elements S and P are controlled, Cr oxidation is restrained, and inclusion is controlled; and annealing demagnetization is not needed, and the non-magnetic stainless steel is obtained and used for electronic product structural parts and stainless steel frames.

Description

technical field [0001] The invention belongs to the technical field of stainless steel production, and in particular relates to a non-magnetic stainless steel and a production method thereof. Background technique [0002] As we all know, magnetism is a kind of problem often encountered in stainless steel parts for electronic equipment. It is desirable to use non-magnetic materials for camera components, navigators and mobile phone structural parts. Although 304 (Cr-Ni) and 316L (Cr-Ni-Mo) austenitic stainless steels are conventionally classified as non-magnetic steels, they often retain or produce certain magnetism due to compositional differences or processing effects. However, general austenitic stainless steel is limited by its composition, and the content of austenitic stable elements is insufficient. At room temperature, steel generally contains about 5-10% of δ ferrite, so it is slightly magnetic. Also because the austenite is not stable enough, part of the austenite ...

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Problems solved by technology

[0006] Chinese patent application, application number 201310039502.0, application date 2013.02.01, authorization announcement date 2014.12.03, authorization announcement number CN103060523B, discloses "a method for smelting non-magnetic stainless steel", but it focuses on the improvement of cracks in quality, and It is only suitable for the production of 0Cr16Ni14 and 0Cr18Ni12 non-magnetic steel, and the product does not contain Mo element

A large amount of austenite-forming element Ni is added to the steel grade. During cold working, the austenite element Ni has a positive effect on expanding the austenite phase region and preventing the formation of martensite. On the other hand, although Mo is ferrite element, but the increase of Mo has a great effect on the corrosion of Cl- ions. Although the increase of Mo increases the cold working magnetic permeability of stainless steel, it can greatly reduce the cold working performance and reduce the magnetic permeability of stainless steel through a large number of austenite element equilibrium phases. corrosion tendency

[0007] Chinese patent application, application number 201610722915.2, application date 2016.08.25, application publication date 2016.12.21, application publication number CN106244944A, discloses "a non-magnetic stainless steel wire rod and its production method", and its products also do not contain Mo element, It cannot solve the problem of Cl ion corrosion such as human sweat, and its austenite element content is low. During the cold working deformation process, martensite will be formed, resulting in an increase in magnetic flux, which cannot meet the requirements of electronic equipment materials.

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